Modular Computed and Direct Radiography Assembly And Method

ABSTRACT

The present invention is directed to a modular scanning apparatus that can be advantageously used in both computed radiology devices and fixed scanning direct radiology devices. The scanning assembly advantageously utilizes a light collecting and measuring assembly having highly reflective surfaces in conjunction with a novel optical assembly within a light box type enclosure to enable a modular scanning and reading assembly that is compact, robust and also scaleable. The present invention further discloses novel computed radiography and direct radiography devices that utilize the modular scanning assembly to provide radiology devices that are highly robust and efficient and yet also simple to build, maintain, service and repair.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/197,221 filed on Aug. 8, 2008.

BACKGROUND

The present invention relates generally to digital radiography systemsand more specifically to modular digital radiography devices and methodsthat can be used in both computed and direct radiography.

Computed radiography (“CR”) systems generate a digital image of an x-rayby scanning an x-ray storage phosphor imaging plate that has beenexposed to x-ray energy, usually while at least partially housed in acassette. The re-useable imaging plate replaces the need for previouslyconventional x-ray film. The imaging plate is typically coated withphotostimulable storage phosphors allowing it to store the energyreceived from the x-ray irradiation. The cassette encases the imagingplate and prevent exposure from ambient and other light sources

In a typical CR operation, the desired object is x-rayed from oneperspective with the imaging pate generally positioned on the oppositeside so as to capture those x-rays passing through the object. Thisresults in a latent image being formed and stored on the imaging plate.Multiple plates may be used for multiple x-rays images of the desiredobject or person or for a larger x-ray image. After exposure by x-rays,the imaging plate is encased in its cassette and taken to a CR systemfor image processing.

The CR device creates an image by stimulating the storage phosphorswithin the imaging plate using a laser beam, typically with a wavelengthbetween 600 to 800 nm, driven across the irradiated area of the imagingplate. Point by point or line by line stimulation by the laser causesthe imaging plate to release light in direct proportion to the latentenergy previously stored as a result of the x-ray irradiation hittingthe surface of the phosphors. The light released by the imaging plate iscaptured by the CR scanning and optical system and converted into anelectrical signal. This signal is then converted to digital data thatcan be manipulated and ultimately viewed on a monitor, printed,transferred to remote systems for further analysis, storage orcomputations.

Various companies produce CR systems with each using slightly differentmeans for exciting the phosphor plate and capturing the released lightenergy as well as handling the imaging plate. The advantages anddrawbacks of these CR systems relative to other radiography systems arewell known. Commonly cited drawbacks include the need to typicallyhandle the imaging plate within a cassette, the burden of moving theimaging plate cassette from the x-ray exposure position to the CR systemand then scanning it to obtain the desired image. in addition torequiring additional handling, these efforts increase the time before animage is actually created by the CR system. Other cited drawbacksinclude the overall size of the system, cost and complexity of thedevices, including the time and costs associated with repairing andmaintenance.

Direct radiography (“DR”) systems arc another form of x-ray imagingsimilar to CR systems in that they typically employ phosphorscintillation materials to generate an image. These systems, however, donot use cassettes containing imaging plates. In a typical DR system, thex-ray energy is directed through the desired object and onto a DRimaging plate assembly. The typical DR imaging plate utilizes phosphorscintillation material bonded to pixel sized sensors. X-ray energyhitting the phosphor layer generates energy that is sensed by each pixelsensor within the detector and sent directly to the DR systemamplifications electronics for generation of the image or other data. Ina DR system, no intermediate steps or processes are required to obtainthe image data.

In addition to generally eliminating the burden and time required tomove the imaging plate cassette from the x-ray position to the CRsystem, most DR systems also advantageously utilize a sealed imagingplate. Because the sealed plate does not need to maintain stored x-rayenergy or be moved for processing, the risk of ambient light or othercontaminants affecting the otherwise stored latent image is eliminated.

In some DR systems, a storage phosphor plate is utilized with a line byline capture of light data using a CCD or CMOS solid state line scanningsensor. These devices are typically limited by the type of sensor usedand the cost of the high light output storage phosphor needed when usinga line by line scanning system. In addition, these devices are typicallyrelatively large in size.

SUMMARY

The present invention is directed to a modular laser scanning andreading apparatus that can be advantageously used in both computedradiology and fixed scanning direct radiology devices. The presentinvention also discloses a novel computed radiology devices utilizingthe modular scanning assembly and novel frame elements. The presentinvention discloses a scanning assembly or scan head for use in adigital radiography device comprising an exterior housing that isadapted to be coupled within the digital radiography device. An opticsassembly is secured within the scanning assembly housing and is adaptedfor generating and scanning a focused laser beam through a narrowelongated opening positioned along one side of the scanning assemblyhousing and that can he directed over an imaging plate. The opticsassembly includes a laser, a scanning assembly and a plurality offolding mirrors that are adapted to scan the laser beam and direct thescanning laser beam through the opening in the scanning assembly housingand over a positioned imaging plate. The scanning assembly also includesa light collection and light measuring assembly secured within thehousing. The light collection assembly includes a plurality of generallyopposing curved reflective surfaces that are adapted to reflect lightreceived through a reading slot in the scanning assembly housing anddirect it to a light measuring device. The light measuring devicesforward the light information to an electronics module for imageprocessing.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and notby way of limitation in the figures of the accompanying drawings inwhich like references indicate similar elements. It should be noted thatdifferent references to “an” or “one” embodiment in this disclosure arenot necessarily to the same embodiment, and such references mean atleast one.

FIG. 1 shows a perspective view of an embodiment of the presentinvention.

FIG. 2 shows an exploded partial assembly view of an embodiment thepresent invention.

FIG. 3A shows a perspective partial disassembled view of an embodimentof CR system of the present invention with the covers removed.

FIG. 3B shows a side view of an embodiment of a partially disassembledframe assembly of the CR system of the present invention.

FIG. 3C shows a front view f an embodiment of the frame assembly of theCR system of the present invention.

FIG. 3D shows a rear view of an embodiment of a partially disassembledframe assembly of the CR system of the present invention.

FIG. 4 shows a perspective view of an embodiment of the scanningassembly adapted for use in the CR device of the present invention.

FIG. 5 shows an exploded view of an embodiment of the frame assembly ofthe CR system of the present invention.

FIG. 6 shows a partial exploded view of an embodiment of the frameassembly and the covers of the CR system of the present invention.

FIG. 7 shows an embodiment of the DR system of the present invention

FIG. 8 shows a perspective view of an embodiment of the DR system of thepresent invention with the outer top cover removed.

FIG. 9 shows an exploded view of the frame assembly of the DR system ofthe present invention showing a rail for supporting a scanning assembly.

FIG. 10 shows a perspective view of an embodiment of the DR system ofthe present invention with the scanning assembly and support rail beinginstalled into the frame.

DETAILED DESCRIPTION OF THE INVENTION

Existing computed radiography (“CR”) designs providing quality imagingcharacteristics and methods are complex and expensive to manufacture,maintain and repair. The problems of expense and complexity ofmanufacture, maintenance and repair are generally deemed worse whenassociated with existing direct radiography (“DR”) designs. In addition,downtown costs associated with maintaining and servicing current CR andDR devices, can be critical with such existing designs.

In the present design and methods, novel modular components andassemblies are provided that find application in both CR and fixedimaging plate scanning devices, including DR applications. The noveldesign and application of these modular systems and components minimizeor avoid altogether, the high costs and delays previously associatedwith repairs and maintenance. For example, the use of the presentlydesigned modular systems generally eliminates the requirement that theradiology device he shipped back to the manufacturer or service facilityfor major service or repair or delays in getting qualified servicetechnicians to the repair site.

More specifically, the present invention discloses a novel modular laserscanning and reading assembly that is adapted to work with drive andframe assemblies and a modular electronics assembly to create a modularbuilt radiology device. The present invention further discloses a novelDR device that provides high resolution images and reliability oftraditional CR devices but retains the compact and scaled imaging plateadvantages of traditional DR devices.

Referring now to FIG. 1, the present invention provides a modularscanning assembly 1 also referred to as a scan head assembly that isadapted for use with both CR and DR type devices. In the illustratedembodiment, the scanning assembly 1 includes an external housing 3 thatis configured to maintain a generally light and dust tight internalenvironment and structurally support the internal optics. An elongatedopening or slit 4 is provided on the underside of the housing 3 andadapted to allow for external scanning of the laser beam and alsoreading of image data from an imaging plate or plates as the scan head 1scans over the imaging plate. The reading slit 4 may be covered with alight transparent material such as a glass to restrict the entry of dustor other contaminants or assist in focusing the laser beam.

The housing 3 preferably includes the ability to remove heat, includingan air vent such as opening 5. To increase the removal of warm air,opening 5 is fitted with a fan 6. The fan 6 is used to move air andparticularly, remove a air from inside the housing 3 and maintain theinternal optics and electronics at preferred operating temperature. Theopening 5 is adapted to restrict light entry into housing 3 and ispreferably fitted with a light restricting brush (not shown) that allowsfor air transfer or similar device to restrict light entry.Alternatively, fan 6 may be used to draw in air, creating a positivepressure environment within the optical assembly and keeping outcontaminants.

The housing 3 is also fitted with an electrical and data connection 7,including an electrical/data plug or receptacle for connection with anelectronics module (not shown) external to scan head 1. The scanningassembly 1 requires electrical power for operation and transfer meansfor transferring image data. Thus, electrical connection 7 may comprisea plurality of electrical and data connection points, including separateports for power and for data transfer.

The housing 3 is also fitted with mounting means for securing thescanning assembly 1 into the desired digital radiology device. In theembodiment shown, the housing 3 is fitted with a pair of mounting pins 8that protrude outwardly from opposing side walls. Pins 8 are adapted tofit into mating slots provided within the desired radiology device.These slots or grooves may include a desired path to assist in theinstallation and removal of the scan head 1. Pins 8 may be made fromsmall diameter rod that is bolted, welded or otherwise secured to theside wall of housing 3. Alternatively, or in addition, scanning assembly1 may be provided with mounting clips or brackets 9. The use of brackets9 allows the scanning assembly 1 to be secured within the desiredradiology device through the use of fasteners that secure to theradiology device.

During installation, pins 8 are inserted into matching slots fittedwithin the frame or housing of a desired radiology device. With the pins8 positioned within their mating slots, scan head 1 may then be rotatedor positioned into the radiology device and preferably, between theframe members. Once positioned, the scanning assembly 1 may be securedto the frame or radiology device housing using fasteners fitted throughbrackets 9. To remove the scanning assembly 1, the fasteners are removedfrom the brackets 9 and the scan head is simply rotated and pulled untilthe pins 8 are withdrawn from the matching slots within the radiologydevice. To fully remove the scan head 1, all electrical and dataconnections (not shown) would also be removed.

By providing radiology devices having matching mounting means, thescanning assembly 1 advantageously provides a modular optical andscanning system that can be readily installed or removed from any suchconfigured device. Most any method of securing the scanning assembly 1within the desired radiology device may be used. The presently describedembodiment only requires two fasteners through mounting brackets 9 andalong with pins 8 and matching slots in the frame members, substantiallyreduces the chance of a failed or incorrect installation. This simpleinstallation and removal procedure eliminates the need for specializedservice technicians for servicing because the entire scanning assembly 1can now simply be replaced with a replacement unit as opposed toservicing or repair.

Referring now to FIG. 2 in conjunction with FIG. 1, an exploded view ofthe scanning assembly 1 is shown and particularly of the novel andcompact optical assembly contained within housing 3. A laser assembly10, includes a laser, galvo and attached rotating mirror assemblysecured together using a novel bracket that preferably also supportsfolding mirror 11. Laser assembly 10, in conjunction with a uniquefocusing mirror arrangement, is adapted for scanning the laser beamthrough the narrow elongated opening 4 oriented along one side ofhousing 3. The supporting “H” style bracket of the laser assembly 10 ispreferably secured within housing 3 using vibration dampening mounts andmethods as are well known.

A light collection assembly 12 is also mounted within the housing 3. Thelight collection assembly 12 includes a plurality of opposing reflectingsurfaces 13 and 14 adapted to reflect light received from the scannedimaging plate (not shown) onto a pair of light measuring andamplification devices 15. Preferably, the light measuring andamplification devices 15 are photomultiplier tubes but may also compriseCCD sensors, CMOS sensors, silicone diode sensors or similar lightmeasuring devices coupled with necessary amplification electronics. Thelight collection assembly 12 is specifically adapted to receive andmeasure light from an imaging plate as it is scanned by a focused laserbeam from laser assembly 10.

Reflecting surfaces 13 and 14 are preferably opposing interiorcylindrical surfaces with an end cap 16 secured and covering each end.End caps 16 are advantageously designed to maintain proper spacingbetween reflective surfaces and aid in reflecting light to lightmeasuring sensors 15. All reflective surfaces are adapted to enhancereflectivity and may be polished. Preferably, reflective surfaces 13 and14 and end caps 16 are covered with a highly reflective coating orsurface layer to ensure the maximum amount of light received from thescanned imaging plate is directed to the photo multiplier tubes 15. Anyhighly reflective coating, polishing or reflective surface material andmethod could be used, including a layer or coating of a syntheticfluoropolymer. In one embodiment, a layer of expandedpolytetrafluoroethylene such as one available from WL Gore & Associates,Inc. is used on reflective surfaces. The reflective material is cut toshape and adhered to and covers the reflective portions of cylindricalsurfaces 13 and 14 and end caps 16. Alternatively such reflectivematerial may also be spray applied, hot melt applied or applied asspecified by the manufacture of the desired reflective material.Reflective coatings and surfaces may and may also be used on allreflective surfaces within the scanning assembly 1. Similarly, all nonreflective surfaces within the scanning assembly 1 may be covered withor coated with a non-reflective material to reduce unwanted lightreflection.

In one embodiment, reflective surfaces 14 and 15 are one piece integralcomponents, including surfaces adapted for mounting and securing othercomponents and are made from an extruded material such as an extrudedaluminum. At least one of the reflective surfaces 14 may include a heatsink 17 for removing heat. Heat sink 17 advantageously removes heat,enabling the use of an integral eraser assembly within the scanningassembly 1. To reduce costs and complexity and increase heat transfer,heat sink 17 or heat sinks are extruded as part f reflective surfaceextrusion 14. In the present embodiment, reflective surface 14 and heatsink 17 form an integral aluminum extrusion that is adapted to secure anintegral erasure assembly 19. The reflective surface 14 and heat sink 17extrusion is further adapted to remove sufficient heat allowing theerasure assembly 19 to operate concurrently during the scanningoperation.

Erasure assembly 19 comprises a light generating assembly adapted toilluminate the imaging plate after scanning to remove the latent imageand ready the plate for further x-ray exposure. Preferably, the erasureassembly 19 comprises a plurality of light elements such as LEDs thatare mounted on a strip and secured to the heat sink 17 so as to ensureheat transfer from the erasure lights to the heat sink. A heat transferinterface may be used between the heat sink 17 and erasure 19 tofacilitate such heat transfer. In an alternative embodiment, a pluralityof erasure assemblies may be used and each may be secured to a heatsink. Additional heat sinks 17 may be extruded as part of eitherreflective surface components 13 and 14 or both, or may he securedthereto. as needed for each particular digital radiography application.Preferably, erasure assembly 19 is spaced apart from scanning andreading slot 4 and separated using a light blocking device such as acaterpillar brush.

In the optical assembly of the present scanning assembly 1, foldingmirrors are advantageously used to reduce the otherwise necessary focallength required to ensure the laser beam from laser assembly 10 remainsfocused as it scans across the entire width of an imaging plate.Specifically, to ensure high quality reading of the data stored onimaging plates, it is imperative the scanning laser beam remain focusedas it scans across the width of the plate. Typically, a focal distanceof over twenty inches is necessary to maintain a focused laser beam on aconventional plate of width not exceeding 14 inches.

The present invention advantageously maintains the relative focal lengthof conventional systems while reducing the actual physical lengthnecessary for such focus. By using a folding mirror arrangement 20 and11 in conjunction with the laser assembly 10 and a reading slot 4oriented perpendicular to the imaging plate, the scanning assembly 1maintains a focused laser beam across scan widths even greater than thatof conventional imaging plates while advantageously reducing the size ofthe optical assembly 12 and thus the scanning assembly as well. Thepresent optical system 12 uses a plurality of front surface reflectivitymirrors as folding mirrors to maintain the desired relative focaldistance. In the presently disclosed embodiment, at least one of thefolding mirrors 20 may be adjustably mounted within the housing 3 toallow for fine focus adjustment of the laser beam. In this embodiment,adjustable mounting bases 21 secure each end of the elongated returnfolding mirror 20. Rotating adjustment screws within the mounting bases21 acts to advantageously adjust the folding mirror 20 along twodimensions.

The embodiment shown utilizes three front surface reflectivity mirrors20 and 11 to fold light in the corners, At least one of the mirrors 20is generally the width of the widest desired imaging plate with anothermirror 11 being much narrower and secured to the styled bracket of thelaser assembly 10. The novel design of the present scanning assembly 1provides for scaleability such that the laser beam may be maintained infocus across a wider scan width through minor adjustments to the laserassembly 10 and folding mirror arrangement 20 & 11 and only requiringcorrespondingly wider folding mirrors and scanning assembly. ComputedRadiography Application.

Referring now to FIGS. 3A-3D, a specific embodiment of the presentinvention enables an image reading device 50 utilizing an embodiment ofthe scanning assembly of the present invention 52 within a novelelongated frame assembly 54. The modular scanning assembly 52 is adaptedto mount within the frame assembly 52 in a plug and play fashion tofacilitate the assembly, maintenance, repair and disassembly of theimaging device 50. In the embodiment shown, the modular scanningassembly 52 is secured to the frame assembly 54 between the generallyparallel elongated frame members 55 and 56 using a four point connectionmeans.

The computed radiology (“CR”) imaging device 50 includes a cassettecarriage module 58 for supporting an imaging plate cassette assemblysuch as the one described in U.S. Pat. No. 7,375,350 to Stephen Neushul.The carriage module 58 may also be adapted to support an imagingcassette and plate of most any size that can be driven within the frameassembly 54 such that the desired portion of the imaging plate (notshown) is driven past the scan head 52.

A drive assembly 66 is secured to one side of the frame assembly 54along frame member 55 and also coupled to the moveable carriage assembly58. The drive assembly 66 is adapted to move the carriage 58 and anyinserted imaging plate cassette from a first position at one end of theframe assembly 54 generally parallel with the elongated frame members 55and 56 to a second position nearer the opposite end of the frameassembly such that the carriage assembly is driven over the scanningassembly 52 such that the imaging plate can be scanned. A carriagesupport plate 76 is coupled to the moving portion of the drive assembly66 at one side and slideably coupled along an elongated rail 78 (FIG. 5)on the other side that extends along the length of frame member 56. Thecarriage 58 may also be supported by a second elongated bearing typerail support positioned parallel to and generally adjacent the driveassembly 66. The rails 78 may be supported and attached to frame members55 and 56 through rail supporting members or directly attached with postsupports, fasteners, welding, or any other method as is well known.

An electronics module 80 is secured between frame members 55 and 56. Theelectronics module includes electrical couplers adapted to connectdirectly to the scan head module 52. In the embodiment shown, theelectronics module 80 is secured within the frame assembly 54 betweenframe members 55 and 56 using a plurality of screws secured throughbrackets 82 on the frame module extending into the frame members. Theelectronics module, like the other modules and components of the presentinvention, may also be secured to the frame assembly 54 using otherfastener types and securing means as are well known in the art.

A frame end cap 86 secures the side frame members 55 and 56 at one endand advantageously acts to provide closure for the end of the CR device50. In the embodiment shown, the end cap 86 acts as a base for the CR 50and supports feet 88 adapted to prevent movement on the supportingsurface and also to reduce vibration. Base supports 88 may be a rubberbase that is secured to end cap 86 or alternatively any type of base orfooting material may be used, such as the four pliable feet screwed intothe end cap as shown in the Figure . An upper lateral frame member 89extends laterally between frame members 55 and 56 and adds structuralrigidity to the frame assembly 54 and further provides mountinglocations for an exterior enclosure. Although the frame members 55. 56and 87 and end cap 86 in the present embodiment are secured togetherusing machine screws, they may also be secured using any other commonmeans of fastening, including welding or even build from formed pieces.

Referring now to FIG. 4, the modular scanning assembly 52 includes ahousing 60 that is adapted for removable attachment to the frameassembly 54 to facilitate its installation, servicing and removal. Thehousing 60 includes an exhaust vent 61 that preferably incorporate acooling fan and brush system to vent warm air without allowing ambientlight penetration and electrical connectors 63 for electrical and dataconnection with the electronics module 80. Scanning slot 67 provides anopening within the housing 60 for the laser beam scanning and receivingthe emitted light for measuring and reading the image. Erasure assembly69 is secured to housing 60 and is adapted tar removing any latent imageon the imaging plate.

Brackets 62 extend from the scan head housing 62. Each bracket 62 isadapted to accept a fastener for securing the scan head 52 to the frameassembly 54. The brackets 62 show have holes for a fastener (not shown)to pass through and secure the scan head 52 to the respective framemembers 55 and 56. Alternatively, the brackets 62 may be adapted todirectly connect to a fastener, pin, clip, hook or other coupler fixedto the frame assembly 54 or the brackets may extend from the frameassembly 54. The brackets 62 may be constructed as part of the scan headhousing 60 or secured to it using one of the many well known techniquessuch as fastening, riveting, welding, adhesion or a combination.

In addition to brackets 62, the housing is also fitted with pins 64located on opposite sides of the scan head housing 60. Each pin 64 isadvantageously designed to mount into a slot 65 (FIG. 5) fitted to eachframe member 55 and 56. The slot 65 is advantageously designed to allowfor simply inserting and exact positioning of the scan head within theCR device 1. Thus, in the embodiment shown, the scan head module 52 isinstalled and removed using a four point attachment means and throughthe use of only two fasteners that secure it to the frame assembly 54.

Referring now to FIG. 5, in conjunction with FIGS. 3A-3D, the driveassembly 66 includes a drive means 68, such as an acme type screw, thatmoves a drive plate 72 as it rotates or is otherwise driven. Spacedapart bearings 70 rotateably support the drive screw 68 and also securethe drive assembly 66 to the frame member 56. An electric motor 74 isattached to the drive screw 68 through coupler 75 and acts to rotate it.Preferably bearings 70 or similar rotation supporting devices arclocated adjacent the ends of the drive screw 68 and as illustrated,secured to the frame member 56 using vibration reducing mounts andmachine screws to ensure rigid vibration free support while allowingmaximum drive plate 72 travel. For longer travels that necessitateadditional drive axle support, additional support bearings may be usedthat are slideably attached to an elongated bearing or bushing supportrail that is in turn secured to the frame assembly 54.

The drive plate 72 is secured to the drive screw 68 through a driveblock 73 that is driven along the drive screw 68 as it rotated by theelectric motor 74. The drive assembly 66 is designed to be modular so asto facilitate installation, maintenance, repair and removal and well asto provide a very accurate and smooth drive mechanism. The driveassembly 66 could also be made using other means that accomplishaccurate and smooth movement of the carriage assembly 58 along thelength of the elongated frame members 55 and 56. For example, thepresently described drive assembly 66 may be replaced with a linearmotor assembly, a belt drive assembly a rack and pinion drive or anyother drive means as commonly known in the art.

Referring now to FIG. 6, an embodiment of the CR device 50 is shown withthe drive module 66, electronics module 80 and scan head modules 52installed within the partially disassembled frame assembly 54. To ensurethe CR device 50 is light and dust tight, a back cover 89, upper frontcover 90 and lower front cover 91, as well as top cover 92 are securedto the frame members 55 and 56. In one embodiment, covers, 89, 90, 91and 92, are constructed from formed sheet metal, such as aluminum butmay also be made from most any other durable material, includingplastics and composites. The covers 89. 90 and 91 may be attached to theframe assembly 54 using machine screws or any other well known method,including, but not limited to, welding, snap fit, adhesives, formedcovers that fit into slots, rivets, etc. The lower cover 91 isadvantageously designed for removability and access to the scan head 52and electronics module 80.

Upper cover 92 includes and opening slot 93 for receiving an imagingplate and particularly and imaging plate cassette. The opening slot 93includes means for restricting the entry of ambient light when theimaging cassette is inserted as well as when it is removed. These meansfor restricting outside light may include a light restricting brush orbrushes placed along the length of the slot, gaskets, as well as othermeans as commonly used in the art.

The frame assembly 54 is advantageously designed to form an exoskeletonthat is sufficiently robust for a mobile type CR unit and rigid enoughto support the precision drive module 66 and maintain the cassette drivepath. The exoskeletal frame assembly 54 comprises a plurality ofelongated side members that fit together and mate to form the generallyopposing side frame members 55 and 56 which are secured to upper lateralframe member 87 and lower end cap 86. Although the lower frame end cap86 and lateral frame member 87 are designed as separate members that aresecured to the elongated frame members 55 and 56 using screw fasteners,they may also be welded, joined through a mechanical tongue and slotfitting without or with less fasteners, secured using any form offasteners, welded together, or even formed as part of the elongated sideframe members.

In the embodiment shown, the frame members 55 and 56 each comprise apair of extruded aluminum members that are joined along mating elongatededges to form a lightweight combination outer side wall and framemember. Specifically, frame member 55 is made from an angle extrusion 95joined along an elongated side with a side extrusion 97. Similarly, sideframe member 56 is made from an elongated angle extrusion 96 joinedalong an elongated edge with an elongated side extrusion 98. Each angleextrusion 95 and 96 is formed and adapted to geometrically mate, in atongue and groove fashion, with the corresponding side frame member 97and 98 along the mating elongated sides. The tongue and groove jointpreferably extends along the length of the joined edges to increaserigidity, eliminate the need for fasteners and also prevent lightintrusion. Joining each angled frame member 95 and 96 with respectiveside frame members 97 and 98 is readily accomplished by placing anextended tongue or lip that extends along the elongated side of theangled extrusion into a mating receiving groove or slot formed withinthe respective side frame member and rotating until the lip locks intothe groove. Although the frame members could he secured using fasteners,adhesives or even welded together, the extruded tongue and groovecreates a rigid assembly without the need or expense of such assemblies.

By using extrusions 95 and 97 and 96 and 98 that are paired together ina tongue and slot fashion and are further uniquely formed for thespecific CR device application along with lateral frame members, thepresent embodiment provides a rigid chassis assembly 54 capable ofsupporting the required device modules 52 and 80 and drive system 66. Inthis embodiment, the drive system 66 is supported and secured betweenthe angled frame member 96 and the side frame member 98. In addition,the angled extrusions 95 and 96 are each advantageously formed withsecuring means for the scanning assembly 52, including slots 65 forreceiving pins 64 and brackets 62 along with supporting surfaces formounting rails 78 and for supporting the exterior covers of the CRdevice 50 such as lower front cover 91.

Direct Radiography Application.

Referring now to FIG. 7, another specific embodiment of the presentinvention enables a direct radiography type (“DR”) image reading device100 utilizing an embodiment of the inventive scanning assembly. Similarto the CR device embodiment, the present modular scanning assemblyreadily mounts within a rigid frame assembly 104 to facilitate theassembly, maintenance, repair and disassembly of the DR type imagingdevice 100. In contrast to the CR device 50 of FIGS. 3A through 6,however, the present DR embodiments function by moving the scanningassembly along the elongated length of the DR device and over an imagingplate that is generally fixed in position and secured to the frame.

Referring now to FIGS. 8 and 9, the frame assembly 104 of the DR device100 comprises a pair of generally opposing elongated side frame members105 and 106 and generally opposing lateral side members 108 and 109. Theframe assembly 104 is advantageously designed to form an exoskeletonthat is sufficiently robust for a mobile type DR unit and rigid enoughto support a precision drive system 110 and operation. The frameassembly 104 is further adapted to receive and support a scanningassembly 102. Similar to the CR system embodiment of the presentinvention, the elongated frame members 105 and 106 are preferably madefrom an extruded aluminum or other extruded metal. Opposing lateralframe members 108 and 109 are also preferably made from an extrudedmetal but may also be made from a plastic.

Drive assembly 110 is modular and similar to the disclosed driveassembly 66 utilized in the CR device 50 of FIG. 3 and includes a drivemotor 111 coupled to a drive mechanism 112 through a shaft coupling 113.The drive mechanism 112 may be a drive screw, such as an acme typescrew, that moves a mating internally threaded drive block 114 along itselongated axis as it is rotated by motor 111. In one embodiment, thedrive motor is an electric motor with spaced apart bearings 115rotateably supporting the acme type drive screw 112. The bearings 115are preferably secured within a mount that secures the drive assembly110 to the frame member 106 through a plurality of vibration mounts andfasteners.

For imaging devices, including the DR device 100, having longer travels,additional support bearings 115 may be used to ensure a precision drivepath is maintained. Alternatively, support hearings may be used thatslide along an elongated bearing or bushing support rail that is in turnsecured to the frame assembly 106 as well as increased drive assembly110 components, including drive screw 112. Alternatively and aspreciously discussed, different drive assembly may be used altogether solong as it maintains the necessary precision drive characteristics.

A drive block and bracket 114 is secured to the scan head module 102.The drive block 114 mates with the drive screw 112 such that when motor111 is rotated, the scanning assembly 102 is moved along rails 103 thatare secured to each frame member 105 and 106. A plurality of side railbearings 116 slideably couple the scanning assembly 102 to elongatedrails 103. In the embodiment shown, multiple spaced apart bearings 116are secured to one side of the scanning assembly 102 and the adjacentside rail 103 and a single bearing is coupled to the other side of thescanning assembly and coupled to the respective side rail. This designadvantageously resists torque from transferring from the drive assembly110 to the scan head 102 during operation. Rails 103 may be made fromsmooth elongated rods or cylinders and preferably from a non-corrodingor static producing material such as a stainless steel or one having aplastic surface or coating.

Similar to the disclosed CR embodiments, the DR device 100 includes anelectrical interface 117 that is secured to one of the frame members 104or 106 and is adapted for connection to a source of electrical power,such as a wall or other electrical outlet or battery supply. Theelectrical interface 117 is preferably also adapted to electronicallyconnect with any desired receiver of image information, such as acomputer, network, printer or the like though such connection may alsobe made using wireless methods as known in the art or transmittinginformation wirelessly. Electrical interface 117 is also adapted toelectronically interconnect with the internal components, including thescanning assembly 102, the drive assembly 110 and the electronicsmodule. Preferably all internal interconnects are with plug type wiringharnesses but may be interconnected using other means as is also wellknown. The electrical interface 117 may also he provided using multiplepoints of interconnection so as to facilitate wiring and the moduleassembly of device 100.

Referring now to FIG. 10, the scanning assembly 102 is shown partiallyinstalled or removed from the frame assembly 104. In this embodiment,the scanning assembly 102 is installed or removed by simply uncouplingone or both of the rail supports 119 from frame assembly 104. Railsupports 119 are secured to lateral frame elements 109 and 109 through aplurality of fasteners. The scanning assembly 102, rails 103 and railsupports 109 can then simply be lifted out and removed from within theframe assembly. To fully remove the scan head 102, the electricalcouplings between it and the electronics module and electrical interfacemust also be disconnected. Alternatively, the rail bearing 116 opposingthe drive assembly 110 side may be a partial cylinder bearing such thatit can be removed and installed on the rail 103 by merely lifting it offthe rail. In this way, scanning assembly 102 may be removed andinstalled by simply removing the two rail supports 119 on the drive siderail 103. Alternative embodiments are contemplated wherein the scanningassembly 102 is secured to the DR device 100 through using any varietyof fasteners. clips or other well known methods. In another embodiment,vibration dampeners are used between the scanning assembly 102 and theframe assembly 104.

Once the scanning assembly module 102 is installed into the frameassembly 104 as generally illustrated in FIG. 8, the drive block andbracket 114 may he connected to the scanning assembly. An electronicsmodule and imaging plate module (not shown) are also installed withinthe frame assembly 104 in similar fashion to the disclosed CR deviceembodiment of the present invention. An upper exterior cover 118 asillustrated in FIG. 7 and a lower exterior cover (not shown) are securedto the frame assembly 104 to provide further structural integrity whileexcluding light, dust and contaminants. Covers 118 are secured to theframe assembly 104 through fasteners though any method of securingtypical sheet metal, plastic, composite or similar covers may be used.In the present embodiment, removal of the upper cover 118 allows accessto the modular components, such as the scanning assembly 102.

An imaging plate, such as a phosphor plate (not shown) may be secured toa support backing, such as a carbon fiber plate, that is in turn securedto frame assembly 104. The support backing is preferably transparent tox-rays and may be made from a carbon fiber, a glass or any other x-raytransparent material and may even be a plurality of materials with onlythe ‘read’ area being made from x-ray transparent materials. The supportbacking provides a rigid support for the imaging plate and means forreadily securing it to the frame assembly 104. The support backing maybe secured to the frame members 105 and 106 using fasteners andpositioned such that the scanning assembly 102 and particularly, thescanning and reading slot 4 of FIG. 1 can be moved over the entireplate.

The imaging plate may be glued or otherwise adhered to backing or may besecured using any other means or methods as commonly known. In oneembodiment, a flexible phosphor plate of approximately 14 inches by 17inches is adhered to an approximately 15 inch by 19 inch byapproximately ¼ inch thick carbon fiber backing plate. In anotherembodiment, a phosphor imaging material, such as a needle or splinedphosphor is directly deposited on the x-ray clear backing plate. Toenhance durability and prevent contaminants, a protective surface orcoating that is also clear to x-rays, such as a carbon fiber plate, maybe applied over the needle phosphor material.

Other Embodiments

In another embodiment of the present invention, the scanning assembly ofthe present invention is adapted for scanning larger imaging plates. Inthis embodiment, the scanning assembly is used in conjunction with adigital radiology device that is adapted for use with longer or evenmultiple imaging plates such that the scanning head assembly is allowedto continuously or incrementally scan along a longer run. This may heaccomplished using a longer drive assembly and support rails within anembodiment of the present radiography device. Such embodiment isadvantageously adapted for use with longer imaging plates, multipleadjacent imaging plates or even scanning along a roll of imaging platematerial. In one embodiment, the scanning head assembly is used within alonger digital radiography device of the present invention so as to scana series of plates along the entire length of a human patient.

In another embodiment of the present invention, the scanning assembly ofthe present is adapted for use as an independent radiology device. Inthis embodiment, the scanning assembly may include internal electronicsfor processing or preliminary processing of image data of may simplytransfer such information for processing by another device. The scanningassembly is coupled with an imaging plate support assembly and a lighttight enclosure. The imaging plate support assembly is preferablyadapted to support any desired imaging plate or imaging plate cassette.Alternatively, the scanning assembly may be adapted to he moved along acurved or non linear plurality of support rails to allow for reading ofcurved imaging plates.

The foregoing description of the embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsor methods disclosed. Persons skilled in the relevant art can appreciatethat many modifications and variations are possible in light of theabove teaching.

1. A scanning assembly for use as part of a radiography device, saidscanning assembly comprising: An exterior housing adapted to beremoveably supported within the radiography device and to restrict thetransfer of light through said housing; An optics assembly securedwithin the exterior housing and adapted for generating and scanning afocused laser beam through a narrow elongated opening positioned alongone side of the housing, said optics assembly comprising a laser and arotating mirror assembly, a plurality of folding mirrors adapted fordirecting the scanning laser beam through the elongated opening in thehousing; and a light collection assembly having a plurality of generallyopposing curved reflective surfaces and a light measuring device; Anerasure assembly coupled to the optics assembly and secured within thehousing and adapted to remove latent image information stored in aphosphor imaging plate used with said radiography device. Wherein andthe light collection assembly is adapted to receive and measure lightreceived from the elongated opening in the housing and at least one ofsaid folding mirrors is adjustably mounted within said housing.
 2. Thescanning assembly of claim 1 wherein at least a portion of thereflective surface is an expanded polytetrafluoroethylene.
 3. Thescanning assembly of claim 1 wherein the laser and rotating mirrorassembly further comprises an adjustable support base mounted within thehousing and adapted to allow relative adjustments of the laser scanning.4. The scan scanning assembly of claim 1 wherein the erasure assembly isdirectly coupled to a heat sink.
 5. The scanning assembly of claim 4wherein at least one of the reflective surfaces and the heat sinkcomprises a single component that is made from an extruded alloymaterial.
 6. The scanning assembly of claim 1 wherein the plurality offolding mirrors comprises three front surface reflectivity mirrors. 7.The scanning assembly of claim 1 wherein the reflective surfacescomprises a pair of opposing concave reflective surfaces that areoriented such that light contacting the surface is reflected to thelight measuring device.
 8. The scanning assembly of claim 7 wherein thelight measuring device comprises a plurality of photo multiplier tubescoupled to at least one of said reflective surfaces.
 9. The scanningassembly of claim 1 wherein the opposing reflective surfaces comprises aplurality of opposing interior cylindrical surfaces that are spacedapart to provide a narrow elongated slit in-between, at least one ofsaid cylindrical surfaces having an opening oriented perpendicular toits axes and adapted to receive the light measuring device, and whereinat least a portion of the opposing interior surface are lined with asynthetic fluoropolymer.
 10. The scanning assembly of claim 1 whereinthe housing is light tight and adapted to only allow light through theelongated narrow opening between the reflective surfaces.
 11. Thescanning assembly of claim 1 wherein the housing further comprisescoupling means for positioning and mounting the scanning assembly withinthe radiology device.
 12. A radiography device for use with an imagingplate cassette comprising: A frame assembly having a plurality ofelongated frame members spaced apart along a parallel axis; A removablescanning assembly having a housing removeably coupled between the spacedapart elongated frame members, said scanning assembly further comprisingan optical assembly and a light collecting assembly and adapted forscanning a focused laser beam across and measuring light energy receivedfrom the imaging plate cassette; A cassette carriage assembly moveablycoupled to at least one of the elongated frame members and adapted forsupporting the imaging plate cassette; A drive assembly coupled to thecassette carriage assembly and to at least one elongated frame member,said drive assembly adapted to move the cassette carriage relative tothe scanning assembly so that an imaging plate within the cassettecarriage may be scanned by the scanning assembly; and A plurality ofcovers coupled to at least one of the elongated frame members so as toenclose a substantial portion of the radiography device; Wherein theplurality of covers comprises a movable cover adapted to allow access tothe scanning assembly such that said cover may be moved allowing thescanning assembly to be removed from the radiography device.
 13. Theradiography device of claim 12 further comprising an electronics modulethat is electronically connected to the scanning assembly and to thedrive assembly, said electronics module adapted for controlling theoperations of the scanning assembly and drive assembly so as to acquireimaging data from the scanning assembly.
 14. The radiography device ofclaim 12 wherein the elongated frame members comprises an extrusion froman aluminum alloy.
 15. The radiography device of claim 12 wherein eachelongated frame member comprises a plurality of elongated frame membersmechanically coupled together to form an integral frame member.
 16. Theradiography device of claim 12 wherein the optical assembly is adaptedfor generating and scanning a laser beam through a narrow elongatedopening along one side of the housing and the light collection assemblyfurther comprises a plurality of reflective surfaces that are adapted toreflect light received from a laser scanned imaging plate to a lightmeasuring device; Wherein at least a portion of the reflective surfacescomprises a synthetic fluoropolymer to enhance reflectivity.
 17. Theradiography device of claim 12 wherein the synthetic fluoropolymer is anexpanded polytetrafluoroethylene.
 18. The radiography device of claim 12wherein the removable scanning assembly further comprises an erasureassembly coupled to the light collection assembly and is adapted foraltering the energy stored in the imaging plate after being scanning bythe laser.